Oh your tears. Your beautiful, delicious, tears.
Not that I really disagree with this truthbomb, but...
a) The discussion is about Microsoft's management of first-parties in the console gaming space over the past thirteen years, so all the great stuff they did in the past in the PC space doesn't apply, especially considering the trainwreck that has come since.
b) The list of not-related-to-the-topic look-at-Microsoft's-contributions bullet points is a good one; however, the PC parts/online multiplayer/hard drive stuff dates back to the original Xbox and Xbox Live (so 2001/2002), and honestly I personally feel they've done nothing to "improve" their offerings since, instead plastering advertising and paywalling tons of shit behind their "great" console online offering and trying to do things like the awful GFWL. (I'll give them full points for the indie push, but the architecture comment just seems like unnecessary tire pumping.)
c) I don't think anyone is arguing that Microsoft's money-hatting or throwing-of-money-at-existing-studios-to-get-exclusives hasn't led to some great titles, but more that they haven't really done anything to foster/develop acquisitions further or spin up new studios. Hell, of the games you listed, three of the five were developed by "acquired" studios, only one of the IPs still being used, and FASA was shut down while Bungie is no longer a Microsoft-managed studio.
The "problem" (if you consider it a problem, but in the context of this thread, that's the "problem" being debated, anyway) is that they've had 13 years in the console space and have no real "stable" to speak of, at least when you compare it to the other two. Turn 10 might be the only one "spun up" that is still around, and pretty much all of their notable/noteworthy acquisitions were subsequently shut down or left, whereas the other two pubs still have not-insigificant in-house or acquired studio development, and have been able to make franchises out of them.
We're in an era where both Sony and Microsoft are pouring boatloads of money into "content denial" strategies instead of "content creation" ones, and many people find that distasteful. Fund Platinum to make a game on your console -- great. Pay a company a boatload of cash to make games/content "exclusive" to your console for a period of time -- not great. One of these leads to more content overall, one of these leads to the same amount of content through fewer channels.
I do think that Microsoft gets a lot of flak, but it really is befuddling that they've managed to completely botch this part of it, especially considering their "good old days" strengths in the PC market. It becomes more than befuddling when it leads to less things overall, in the name of trying to compel you to buy their hardware.